The LM339 Quad Comparator is an excellent component to have in your parts bin. It is extremely versatile can can be used for basic inverting and non-inverting amplifiers.
These devices consist of four independent precision voltage comparators with an offset voltage specifications as low as 2mV max for LM339A, LM239A and LM139A. All these comparators were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible.
With a wide single supply or dual supply voltage range up to +36V and TTL and CMOS compatible outputs, it can be applied to almost any circuit with few external components.
The LM339 is rated for a temperature range of 0°C, +70°C. If a wider temperature range is needed. the LM239 or LM139 can be substituted giving a maximum temperature range of -55°C, +125°C.